Abdominal Radiology 2 Flashcards
CT scan Abdomen/Pelvis
- Most common procedure for abdominal pathology - “answer machine”
- IV contrast- vascular structures, organs
- Oral contrast- allows differentiation of bowel from other abdominal tissues
- Rectal contrast – colon
- Anatomy and level of slice – key
- CONTRAST, KIDNEYS, CREATININE
- Mesenteric or local sign of inflammation: “fat stranding” - can only be found on CT
- Fluid collections
CT abdomen and pelvis
-Base of lungs to femoral heads
-As you click through, what level are you at?
What is coming into view at that level?
Imaging the Intestines/Colon: Colonoscopy/CT scan
- Bowel Obstruction - +/- Plain Film/CT w/ IV con
- Bowel Ischemia - CT w/ oral and IV con
- Diverticulitis - CT w/ oral and IV con
- Colitis - CT oral and IV con/Colonoscopy/Barium (Ulcerative Colitis, Crohn’s Disease, TM: emergent vs non-emergent)
- Colonic polyps - colonoscopy, barium
- Tumors – Colonoscopy, CT w/ oral and IV con
Small bowel obstruction on CT
-Dilated, fluid-filled small bowel -Thickening of bowel wall -Air-fluid levels -CT best, most sensitive test for site of obstruction and cause -Radiologist to confirm
Large bowel obstruction
- Huge, dilated loops
- Haustra
- SB collapsed
- LBO on CT
- CT best for site of obstruction
Diverticulosis
-Large bowel
-Air-filled “outpouchings”
-At edge of bowel wall
-No fat stranding to suggest
inflammation
Diverticulitis
-Inflammation, infection or abscess of diverticuli
-Sigmoid location
common
-Local fat-stranding, thick, edematous bowel wall
Target sign on CT
DDX: -Crohn’s Dz -Ulcerative Colitis -Ischemic Bowel -Intussusception
Appendicitis
- Children – Ultrasound first (Wall thickness > 6 mm, Non compressible appendix)
- Adults- CT abdomen/pelvis with IV contrast (only) (Edema, inflammation (fat stranding), Dilated appendix > 6 mm diameter)
- Adults - Ultrasound - thin, pregnant (Non-compressible, >6mm diameter)
- Classic location
- Thickened wall
- Peri-appendiceal fat-stranding
- Appendolith
- Dilated >6mm: US
- Rupture? Abscess?
Hernias on CT
- Where are these hernias located?
- Fat stranding, inflammatory changes may indicate strangulation
Pancreatitis
- Pancreas crosses the midline
- ETOH, Rx drugs, viruses, gallstones, etc
- CT - oral and IV best
- ULS the biliary tree if suspect pancreatitis (Gallstone Pancreatitis)
- ERCP/MRCP (Gallstone pancreatitis, ERCP itself can precipitate pancreatitis
- Gallstone pancreatitis: stone in common bile duct that obstructs Ampulla of Vater and lodges in Spinchter of Odi, blocking pancreatic bile, enzyme discharge
The abdominal aorta
- Identify it on all CT’s
- Located just superior to vertebral body in axial view
- Follow it to the bifurcation
- Size?
- Calcifications?
- Contrast in lumen uniform?
pneumoperitoneum on CT
- Air or gas in the peritoneal cavity
- CT – (best test) “double wall sign”, falciform ligament
CT of Biliary system
- Where is the problem?
- Ultrasound - the first test
- ERCP/MRCP useful
- CT is not the first test for diseases of the biliary tract
- CT biliary tract findings incidental or for extent/other organ involvement
- CT best for emphysematous cholecystitis
Gallbladder on CT
-Cholecystitis (Enlarged, thickened wall, Fat stranding surrounding GB)
-Emphysematous Cholecystitis
Air around gallbladder (Infection by gas-producing bacteria, NOT seen on ultrasound!)
-CT is less sensitive for identifying gallstones than ultrasound and is NOT the initial test of choice.
-Air is the enemy of ultrasound!
